In tracks, in particular of tracked vehicles, the links of the track are typically connected with each other via pivot pin hinges. For this purpose, such a pivot pin hinge comprises a pin and a sleeve that is rotatably suspended around the pin. Links of the track are press-fit on the respective ends of the pin and the sleeve. The pivot bearing surfaces between the pin and the sleeve are lubricated by an oil reservoir in the pin. The oil chamber between the pin and the sleeve is sealed by two sealing elements that comprise sealing lips pressing against the end faces of the sleeve.
A track pin assembly having such a seal is known, for example, from DE 27 26 033 A1 and its English-counterpart U.S. Pat. No. 4,094,516 and comprises a track pin attached to a portion of a first track link and a bushing attached to a portion of a second track link. The bushing surrounds a portion of the track pin and is reciprocally movable relative to the track pin. A cavity is defined in the first track link for receiving the seal having a sealing lip for abutment on an end face of the bushing. A spacer ring surrounds the track pin and extends in the axial direction between an end face of the cavity and the end face of the bushing. The seal is inserted in the hollow space defined in the cavity and comprises a primary seal ring made of a relatively stiff, but elastic, first elastomeric material and a secondary sealing element made of a second resilient elastomeric material that is substantially less stiff than the first material.
A sealing assembly for a track pivot pin hinge is also known from U.S. Pat. No. 4,607,854, which comprises a first ring made of a flexible elastomeric material having a sleeve-like portion, a flange-like portion having a sealing lip, and a second ring made of elastic material contacting the first ring for sealing a space between a pin and a sleeve surrounding the pin. The first ring comprises a cylindrical, metallic reinforcing ring that is completely embedded in the sleeve-like portion of the first ring.
A sealing assembly and a track link are also known from DE 10 2006 050 439 A1 and its English-counterpart US 2010/0148572. This sealing assembly comprises a sealing ring having a sealing edge that sealingly abuts on an element of the track. A metallic support ring is embedded in the sealing ring for reinforcing the sealing assembly. An elastic ring is pushed onto the support ring and has a sealing lip that abuts on a further element of the track.
U.S. Pat. No. 4,256,316 discloses a joint sealing structure for sealing two joint parts that are axially movable relative to each other and includes a seal ring having a sealing lip for maintaining a dynamic seal with a sealing surface of one of the joint parts. A stiffener is provided for transferring a biasing force from a spring means to the sealing lip. The stiffener includes a flexible connecting portion permitting free movement of the sealing lip under the biasing action of the spring means over the range of movement between the joint parts.